Debugging Fails Silently While LS is Starting

[tsmaeder]

When I tried to attach the debugger to a Java program that was still being imported by the Java LS, nothing happend, no success and no error message.

Reproduction Steps

I reproduced this with the Che 7.1.0 and the spring http-booster example (https://github.com/snowdrop/spring-boot-http-booster). Howerver, I think any example that takes a long time to import might help

1. Install the vscode-java extension into theia
2. clear your local .m2 folder
3. import the example project
4. Do not open an java files or do anything to activate the vscode-java extension
5. Run the example in debug mode
   mvn -Duser.home=${HOME} spring-boot:run -Drun.jvmArguments="-Xdebug
   -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=8000"
6. Make a "remote attach" debug config and try to run it
7. Observe: the java language server is started and taking a long time stuck at "57% import maven projects"
8. Observe: nothing else happens

The browser log showed the following exception:

Uncaught (in promise) Error: It is not possible to provide debug adapter executable.
    at DebugExtImpl.<anonymous> (/home/theia/node_modules/@theia/plugin-ext/lib/plugin/node/debug/debug.js:501)
    at step (/home/theia/node_modules/@theia/plugin-ext/lib/plugin/node/debug/debug.js:32)
    at Object.next (/home/theia/node_modules/@theia/plugin-ext/lib/plugin/node/debug/debug.js:13)
    at fulfilled (/home/theia/node_modules/@theia/plugin-ext/lib/plugin/node/debug/debug.js:4)
    at process._tickCallback (/dashboard/internal/process/next_tick.js:68)

[tsmaeder]

Once the language server is through importing, debugging works fine.

[akosyakov]

@tsmaeder Do you remember which versions of vscode-java-debug and redhat-java was it?

[akosyakov]

I can reproduce it with redhat.java@0.47.0 and vscode-java-debug@0.21.0.

But not with latest versions, i.e. redhat.java@0.54.2 and vscode-java-debug@0.23.0.

[akosyakov]

microsoft/vscode-java-debug#728 (comment) - so it is probably not Theia issue

[akosyakov]

Please use redhat.java@0.49.0 or newer.